gasoline vapor is heavier than air. so as long as the source of combustion is at a higher elevation than the gas tank inlet it will not ignite. but put the cigarete below the inlet and it can caught fire. it will not go "booom!". you need a certain ratio of gasoline vapor/air mixture for that to happen. it's like your new year's bamboo cannon, too much kalburo/lighter fluid/gasoline and all you get is a flame shooting out, but get the right mixture and it goes "booom!" i think that only happens in the movies.
i have also tried before throwing a lit cigarete on a half-full pail of gasoline, nothing happened. this is because the gasoline vapor fills the pail to the brim and there is no air/oxygen to mix with it. or maybe i was just lucky ehehehe!


parang mini nuclear explosion yung apoy... tapos nagliyab na yung lata..panic sya. buti na lang may CO2 type fire extinguisher kami, ininsprayan ko agad. 